ATLAS_2012_CONF_2012_153.cc

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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Tools/BinnedHistogram.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/VisibleFinalState.hh"
#include "Rivet/Projections/VetoedFinalState.hh"
#include "Rivet/Projections/IdentifiedFinalState.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Tools/RivetMT2.hh"

namespace Rivet {


  class ATLAS_2012_CONF_2012_153 : public Analysis {
  public:

    /// @name Constructors etc.
    //@{

    /// Constructor
    ATLAS_2012_CONF_2012_153()
      : Analysis("ATLAS_2012_CONF_2012_153")
    {    }

    //@}

    //@}



  public:

    /// @name Analysis methods
    //@{

    /// Book histograms and initialise projections before the run
    void init() {

      // projection to find the electrons
      IdentifiedFinalState elecs(EtaIn(-2.47, 2.47) 
                 & (Cuts::pT >= 10.0*GeV));
      elecs.acceptIdPair(PID::ELECTRON);
      addProjection(elecs, "elecs");


      // projection to find the muons
      IdentifiedFinalState muons(EtaIn(-2.4, 2.4) 
                 & (Cuts::pT >= 10.0*GeV));
      muons.acceptIdPair(PID::MUON);
      addProjection(muons, "muons");

      // for pTmiss
      addProjection(VisibleFinalState(-4.9,4.9),"vfs");

      VetoedFinalState vfs;
      vfs.addVetoPairId(PID::MUON);

      /// Jet finder
      addProjection(FastJets(vfs, FastJets::ANTIKT, 0.4),
                    "AntiKtJets04");

      // all tracks (to do deltaR with leptons)
      addProjection(ChargedFinalState(-3.0,3.0),"cfs");

      vector<double> edges_meff;
      edges_meff.push_back(   0);
      edges_meff.push_back( 150);
      edges_meff.push_back( 300);
      edges_meff.push_back( 500);
      edges_meff.push_back(1000);
      edges_meff.push_back(1500);

      vector<double> edges_eT;
      edges_eT.push_back(0);
      edges_eT.push_back(50);
      edges_eT.push_back(150);
      edges_eT.push_back(300);
      edges_eT.push_back(500);

      // Book histograms
      _hist_electrons = bookHisto1D("hist_electrons_before", 11, -0.5,10.5);
      _hist_muons     = bookHisto1D("hist_muons_before"    , 11, -0.5,10.5);
      _hist_leptons   = bookHisto1D("hist_leptons_before"  , 11, -0.5,10.5);
      _hist_4leptons  = bookHisto1D("hist_4leptons", 1, 0.,1.);
      _hist_veto      = bookHisto1D("hist_veto", 1, 0., 1.);
      _hist_etmiss    = bookHisto1D("hist_etmiss",edges_eT);
      _hist_meff      = bookHisto1D("hist_m_eff",edges_meff);
      _count_SR1      = bookHisto1D("count_SR1", 1, 0., 1.);
      _count_SR2      = bookHisto1D("count_SR2", 1, 0., 1.);

    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const double weight = event.weight();
      // get the jet candidates
      Jets cand_jets;
      foreach (const Jet& jet,
               applyProjection<FastJets>(event, "AntiKtJets04").jetsByPt(20.0*GeV) ) {
        if ( fabs( jet.eta() ) < 2.5 ) {
          cand_jets.push_back(jet);
        }
      }

      // candidate muons
      Particles cand_mu = applyProjection<IdentifiedFinalState>(event, "muons").particlesByPt();

      // candidate electrons
      // Discard if two electrons are within R=0.1
      Particles temp = applyProjection<IdentifiedFinalState>(event, "elecs").particlesByE();
      vector<bool> vetoed(temp.size(),false);
      Particles cand_e;
      for (unsigned int ix=0; ix<temp.size(); ++ix) {
        if(vetoed[ix]) continue;
        for (unsigned int iy=ix+1; iy<temp.size(); ++iy) {
          if( deltaR(temp[ix].momentum(),temp[iy].momentum()) < 0.1 ) {
            vetoed[iy] = true;
          }
        }
        if(!vetoed[ix]) cand_e.push_back(temp[ix]);
      }

      // Sort by transverse momentum
      std::sort(cand_e.begin(), cand_e.end(), cmpMomByPt);

      // resolve jet/lepton ambiguity
      Jets recon_jets;
      foreach ( const Jet& jet, cand_jets ) {
        bool away_from_e = true;
        foreach ( const Particle & e, cand_e ) {
          if ( deltaR(e.momentum(),jet.momentum()) <= 0.2 ) {
            away_from_e = false;
            break;
          }
        }
        if ( away_from_e )
          recon_jets.push_back( jet );
      }

      // only keep electrons more than R=0.4 from jets
      Particles cand2_e;
      foreach (const Particle & e, cand_e) {
        // at least 0.4 from any jets
        bool away = true;
        foreach ( const Jet& jet, recon_jets ) {
          if ( deltaR(e.momentum(),jet.momentum()) < 0.4 ) {
            away = false;
            break;
          }
        }
        // if isolated keep it
        if ( away )
          cand2_e.push_back( e );
      }

      // only keep muons more than R=0.4 from jets
      Particles cand2_mu;
      foreach(const Particle & mu, cand_mu ) {
        bool away = true;
        // at least 0.4 from any jets
        foreach ( const Jet& jet, recon_jets ) {
          if ( deltaR(mu.momentum(),jet.momentum()) < 0.4 ) {
            away = false;
            break;
          }
        }
        if ( away )
          cand2_mu.push_back( mu );
      }

      // electron and muon more than 0.1 apart
      Particles cand3_e;
      foreach ( const Particle & e, cand2_e ) {
        bool away = true;
        foreach( const Particle & mu, cand2_mu ) {
          if( deltaR(e.momentum(),mu.momentum()) < 0.1) {
            away = false;
            break;
          }
        }
        if(away) cand3_e.push_back(e);
      }
      Particles cand3_mu;
      foreach( const Particle & mu, cand2_mu ) {
        bool away = true;
        foreach ( const Particle & e, cand2_e ) {
          if( deltaR(e.momentum(),mu.momentum()) < 0.1) {
            away = false;
            break;
          }
        }
        if(away) cand3_mu.push_back(mu);
      }

      // pTmiss
      Particles vfs_particles =
        applyProjection<VisibleFinalState>(event, "vfs").particles();
      FourMomentum pTmiss;
      foreach ( const Particle & p, vfs_particles ) {
        pTmiss -= p.momentum();
      }
      double eTmiss = pTmiss.pT();

      // apply electron isolation
      Particles chg_tracks =
        applyProjection<ChargedFinalState>(event, "cfs").particles();
      Particles cand4_e;
      foreach ( const Particle & e, cand3_e ) {
        // charge isolation
        double pTinCone = -e.momentum().perp();
        foreach ( const Particle & track, chg_tracks ) {
          if(track.momentum().perp()>0.4 &&
             deltaR(e.momentum(),track.momentum()) <= 0.3 )
            pTinCone += track.pT();
        }
        if (pTinCone/e.momentum().perp()>0.16) continue;
        // all particles isolation
        pTinCone = -e.momentum().perp();
        foreach ( const Particle & p, vfs_particles ) {
          if(abs(p.pdgId())!=PID::MUON &&
             deltaR(e.momentum(),p.momentum()) <= 0.3 )
            pTinCone += p.pT();
        }
        if (pTinCone/e.momentum().perp()<0.18) {
          cand4_e.push_back(e);
        }
      }

      // apply muon isolation
      Particles cand4_mu;
      foreach ( const Particle & mu, cand3_mu ) {
        double pTinCone = -mu.momentum().perp();
        foreach ( const Particle & track, chg_tracks ) {
          if(track.momentum().perp()>1.0 &&
             deltaR(mu.momentum(),track.momentum()) <= 0.3 )
            pTinCone += track.pT();
        }
        if (pTinCone/mu.momentum().perp()<0.12) {
          cand4_mu.push_back(mu);
        }
      }

      // same SOSF pairs m>12.
      Particles recon_e;
      foreach(const Particle & e, cand4_e) {
        bool veto=false;
        foreach(const Particle & e2, cand4_e) {
          if(e.pdgId()*e2.pdgId()<0&&(e.momentum()+e2.momentum()).mass()<12.) {
            veto=true;
            break;
          }
        }
        if(!veto) recon_e.push_back(e);
      }
      Particles recon_mu;
      foreach(const Particle & mu, cand4_mu) {
        bool veto=false;
        foreach(const Particle & mu2, cand4_mu) {
          if(mu.pdgId()*mu2.pdgId()<0&&(mu.momentum()+mu2.momentum()).mass()<12.) {
            veto=true;
            break;
          }
        }
        if(!veto) recon_mu.push_back(mu);
      }

      // now only use recon_jets, recon_mu, recon_e
      _hist_electrons->fill(recon_e.size(), weight);
      _hist_muons->fill(recon_mu.size(), weight);
      _hist_leptons->fill(recon_mu.size() + recon_e.size(), weight);
      if( recon_mu.size() + recon_e.size() > 3) {
        _hist_4leptons->fill(0.5, weight);
      }

      // reject events with less than 4 electrons and muons
      if ( recon_mu.size() + recon_e.size() < 4 ) {
        MSG_DEBUG("To few charged leptons left after selection");
        vetoEvent;
      }


      // or two lepton trigger
      bool passDouble =
        (recon_mu.size()>=2 && ( (recon_mu[1].momentum().perp()>14.) ||
                                 (recon_mu[0].momentum().perp()>18. && recon_mu[1].momentum().perp()>10.) )) ||
        (recon_e.size() >=2 && ( (recon_e [1].momentum().perp()>14.) ||
                                 (recon_e [0].momentum().perp()>25. && recon_e [1].momentum().perp()>10.) )) ||
        (!recon_e.empty() && !recon_mu.empty() &&
         ( (recon_e[0].momentum().perp()>14. && recon_mu[0].momentum().perp()>10.)||
           (recon_e[0].momentum().perp()>10. && recon_mu[0].momentum().perp()>18.) ));

      // must pass a trigger
       if(!passDouble ) {
         MSG_DEBUG("Hardest lepton fails trigger");
         _hist_veto->fill(0.5, weight);
         vetoEvent;
       }

      // calculate meff
      double meff = eTmiss;
      foreach ( const Particle & e , recon_e  )
        meff += e.momentum().perp();
      foreach ( const Particle & mu, recon_mu )
        meff += mu.momentum().perp();
      foreach ( const Jet & jet, recon_jets ) {
        double pT = jet.momentum().perp();
        if(pT>40.) meff += pT;
      }

      // 2/3 leptons --> find 1 SFOS pair in range and veto event
      // 4+  leptons --> find 2 SFOS pairs and in range veto event
      for(unsigned int ix=0;ix<recon_e.size();++ix) {
        for(unsigned int iy=ix+1;iy<recon_e.size();++iy) {
          if(recon_e[ix].pdgId()*recon_e[iy].pdgId()>0) continue;
          FourMomentum ppair = recon_e[ix].momentum()+recon_e[iy].momentum();
          double mtest = ppair.mass();
          if(mtest>81.2 && mtest<101.2) vetoEvent;

          // check triplets with electron
          for(unsigned int iz=0;iz<recon_e.size();++iz) {
            if(iz==ix||iz==iy) continue;
            mtest = (ppair+recon_e[iz].momentum()).mass();
            if(mtest>81.2 && mtest<101.2) vetoEvent;
          }

          // check triplets with muon
          for(unsigned int iz=0;iz<recon_mu.size();++iz) {
            mtest = (ppair+recon_mu[iz].momentum()).mass();
            if(mtest>81.2 && mtest<101.2) vetoEvent;
          }

          // check quadruplets with electrons
          for(unsigned int iz=0;iz<recon_e.size();++iz) {
            for(unsigned int iw=iz+1;iw<recon_e.size();++iw) {
              if(iz==ix||iz==iy||iw==ix||iw==iy) continue;
              if(recon_e[iz].pdgId()*recon_e[iw].pdgId()>0) continue;
              mtest = (ppair+recon_e[iz].momentum()+recon_e[iw].momentum()).mass();
              if(mtest>81.2 && mtest<101.2) vetoEvent;
            }
          }
          // check quadruplets with muons
          for(unsigned int iz=0;iz<recon_mu.size();++iz) {
            for(unsigned int iw=iz+1;iw<recon_mu.size();++iw) {
              if(recon_mu[iz].pdgId()*recon_mu[iw].pdgId()>0) continue;
              mtest = (ppair+recon_mu[iz].momentum()+recon_mu[iw].momentum()).mass();
              if(mtest>81.2 && mtest<101.2) vetoEvent;
            }
          }
        }
      }

      // Muon pairs
      for(unsigned int ix=0;ix<recon_mu.size();++ix) {
        for(unsigned int iy=ix+1;iy<recon_mu.size();++iy) {
          if(recon_mu[ix].pdgId()*recon_mu[iy].pdgId()>0) continue;
          FourMomentum ppair = recon_mu[ix].momentum()+recon_mu[iy].momentum();
          double mtest = ppair.mass();
          if(mtest>81.2 && mtest<101.2) vetoEvent;

         // check triplets with muon
          for(unsigned int iz=0;iz<recon_mu.size();++iz) {
            if(iz==ix||iz==iy) continue;
            mtest = (ppair+recon_mu[iz].momentum()).mass();
            if(mtest>81.2 && mtest<101.2) vetoEvent;
          }

         // check triplets with electron
          for(unsigned int iz=0;iz<recon_e.size();++iz) {
            mtest = (ppair+recon_e[iz].momentum()).mass();
            if(mtest>81.2 && mtest<101.2) vetoEvent;
          }

        // check muon quadruplets
          for(unsigned int iz=0;iz<recon_mu.size();++iz) {
            for(unsigned int iw=iz+1;iy<recon_mu.size();++iy) {
              if(iz==ix||iz==iy||iw==ix||iw==iy) continue;
              if(recon_mu[iz].pdgId()*recon_mu[iw].pdgId()>0) continue;
              mtest = (ppair+recon_mu[iz].momentum()+recon_mu[iw].momentum()).mass();
              if(mtest>81.2 && mtest<101.2) vetoEvent;
            }
          }
        }
      }

      //make the control plots
      _hist_etmiss ->fill(eTmiss,weight);
      _hist_meff   ->fill(meff  ,weight);
      // finally the counts
      if(eTmiss>50.) _count_SR1->fill(0.5,weight);
      if(meff  >0. ) _count_SR2->fill(0.5,weight);

    }

    //@}

    void finalize() {
      double norm = crossSection()/femtobarn*13./sumOfWeights();
      scale(_hist_etmiss,norm*20.);
      scale(_hist_meff  ,norm*20.);
      scale(_count_SR1,norm);
      scale(_count_SR2,norm);
    }

  private:

    /// @name Histograms
    //@{
    Histo1DPtr _hist_electrons;
    Histo1DPtr _hist_muons;
    Histo1DPtr _hist_leptons;
    Histo1DPtr _hist_4leptons;
    Histo1DPtr _hist_veto;
    Histo1DPtr _hist_etmiss;
    Histo1DPtr _hist_meff;
    Histo1DPtr _count_SR1;
    Histo1DPtr _count_SR2;
    //@}

  };

  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(ATLAS_2012_CONF_2012_153);

}